The proposed study is designed to investigate the influence of female sex steroid hormones on psychophysical measurements of detection and pain thresholds and subjective reports of pain in the orofacial region. We will study women with temporomandibular disorders (TMD) at three hormonally distinct times of the menstrual cycle: early follicular phase (low estrogen and progesterone), late follicular phase (high estrogen and low progesterone) and mid luteal phase (high estrogen and progesterone). To characterize further the influence of estrogen and progesterone on pain perception, subjects will use contraceptive medications for the duration of two menstrual cycles during which subjective and objective pain measurements will be recorded. Recent literature strongly implicates the influence of estrogen and to a lesser degree progesterone on pain in the orofacial region. Epidemiologic research has consistently demonstrated that females represent the overwhelmiing majority of orofacial pain and temporomandibular disorder patients. Therefore, we have limited this study to females between the ages of 18 and 45.